1. Field of the Invention
The present invention relates to a recording substrate treatment apparatus, in particular a recording substrate treatment apparatus for a printer or copier. For example, the recording substrate treatment apparatus comprises at least one of a drying device for drying a re-cording substrate and a fixing device for fixing a printing substance on a recording substrate. For example, the fixing device may be or comprise a fuser. The present invention further relates to a printer or printing system comprising a recording substrate treatment apparatus.
2. Description of Background Art
In the field of copying and printing, it is known to dry or fix prints on a recording substrate. For example, a fuser is known for fixing toner powder to a printing substrate, such as a sheet of paper. For example, a fuser comprises a radiant heat lamp, which may be arranged to heat a printing substrate support roller for heating and bonding the toner to the paper.
Fixation of a printing substance to a recording substrate usually involves heating the recording substrate comprising the printing substance and evaporating a solvent and/or water stemming from the printing substance (e.g. an ink).
In inkjet printing, in particular water based inkjet printing on flexible absorbing recording substrates (such as plain paper and machine or offset coated paper), deformation of the recording substrate may occur upon drying of the recording substrate and/or fixation of the printed image on the recording substrate. Such deformation may, at least in part, be prevented by rigidly fixing a recording substrate during drying and fixation. For example, a sheet of a recording substrate may be rigidly fixed on a transportation mechanism by an underpressure force induced by a suction device. The resulting suction flow where no recording substrate is present may have an unwanted cooling effect on the transportation mechanism, leading to energy loss. Recirculation of the suction flow to the recording substrate treatment apparatus may prevent excessive energy loss. However, when recirculating the suction flow (of a gaseous medium, in particular air) build-up of vaporous components in the circulating gaseous medium and originating from the printing substance may occur. Hence, the drying capacity of the recording substrate treatment apparatus deteriorates. Removing such vaporous components requires cooling of the circulating gaseous medium in order to condensate the vaporous components, which again causes an energy loss.
In U.S. Pat. No. 7,354,146, structures and methods are disclosed for at least partially forming an image on a recording substrate on a platen, directing air from a dryer at the platen, and recirculating the air from the platen back to the dryer. Sheets of a recording substrate are held down by an underpressure force. The resulting suction flow may be used to cool the electronics of the printer and is optionally heated before being impinged on the recording substrate to facilitate drying of the recording substrate. A condenser is used to remove vaporous components from the circulating gaseous medium.
It is a disadvantage of recording substrate treatment apparatuses known from the background art that the printed recording substrates are solely dried with a flow of a heated gaseous medium, which is an indirect method of heating. Such recording substrate treatment apparatuses are not suitable for use in a highly productive printer, because of the limited drying capacity of such recording substrate treatment apparatuses.
It is another disadvantage that the entire circulating flow of the gaseous medium needs to be cooled down to remove vaporous components, which is energy inefficient.
In U.S. Patent Application Publication No. 2005/0092200, a printing apparatus is disclosed including a drum having a peripheral surface. In operation of the printing apparatus, a source of heat is used to dry or partially dry any ink that is laid down or placed on the media, which is located on the outer peripheral surface of the print drum. The source of heat is arranged inside the drum and heats the inside surface of the drum.
It is a disadvantage of the printing apparatus disclosed in U.S. Application Publication No. 2005/0092200, because it provides a relatively slow heating method, which is less suitably applied in highly productive printers or printing systems.